Managed to get as far as the dealer (tunes blaring to drown it out!) and the guy on the desk says it would be 35quid to get someone to look because it's 'wear and tear' not warranty
So i thought sod it, went out... reveresed it around the car park a few times... no good. Then a guy comes outta the service bay and asks whats up.... gets on hands and knees, has a feel around behind the wheel, pulls out a stone and its sorted
Can't believe the tosser on the desk wanted £35!!
So yeah, if ever you get a ear piercing screeching from your wheel, try reversing round the block a few times! (The guy said it probably helped dislodge it)